Subsea abrasive jet cutting system and method of use

ABSTRACT

An apparatus for cutting a material underwater is disclosed where the apparatus uses a mixture of abrasive material in a non-aspirated suspension mixed with a high pressure fluid, e.g. seawater. It is emphasized that. this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope of meaning of the claims.

FIELD OF THE INVENTION

The present invention relates to subsea cutting systems. Morespecifically, the present inventions relate to a system and method ofuse of a system for cutting a material subsea using a source of highpressure fluid, a source of abrasive materials where abrasive materialsare present in non-aspirated suspension, and body in fluid communicationwith both.

BACKGROUND OF THE INVENTION

Abrasive materials in cutting systems have been used to aid in rough andprecision cuts. A basic cutting system consists of a filtration system,ultrahigh-pressure pump, nozzle and catcher. A hydraulically drivenintensifier pump may be present to pressurize a fluid such as waterwhere the fluid exits through an orifice, e.g. a nozzle, for cutting amaterial. Abrasive material is typically mixed with the fluid byaspiration, e.g. a cutting head of the nozzle operates pneumaticallysuch that when the cutting system is activated, abrasive is mixed withfluid under pressure and the mixture flows into the cutting head.

Abrasives may further be found in the prior art mixed in with anothersubstance such as a gel, e.g. as a colloidal or emulsified mixture.

A problem exists when attempting to use abrasive cutting systemsunderwater, especially at great depths. A supply system is typicallylocated at the surface of the water and fluid, abrasives, or both aresupplied via an umbilical. Prior art systems are unsuited for use atdepths because of the air or other gas supply typically required toaspirate the mixture for use in cutting.

BRIEF DESCRIPTION OF THE DRAWINGS

The features, aspects, and advantages of the present invention willbecome more fully apparent from the following description, appendedclaims, and accompanying drawings in which:

FIG. 1 is a schematic of first exemplary embodiment of the system;

FIG. 2 is a schematic of second exemplary embodiment of the system;

FIG. 3 is a schematic of an exemplary method of the present invention;and

FIG. 4 is a flowchart of and exemplary method of the present invention.

DETAILED DESCRIPTION OF AN EXEMPLARY EMBODIMENT

Referring to FIG. 1, system 10 is useful for cutting a materialunderwater. In a preferred embodiment, system 10 comprises source 20 ofhigh pressure fluid 22, source 30 of abrasive materials 32 whereabrasive materials 32 are present in non-aspirated suspension 34, andbody 40.

In a preferred embodiment, high pressure fluid 22 is water, e.g. seawater, brought to high pressure from source 20 such as pump 20 a. Incertain embodiments, system 10 further comprises hose 24 which connectssource 20 to body 40.

Source 30 of abrasive materials 32 may comprise any appropriate abrasivematerial such as garnet, bauxite, sand, or taconite or the like or acombination thereof. Hose 36 may connect source 30 to body 40.

In a preferred embodiment, suspension 34 comprises non-aspirated aqueousgel 34 a, preferably gelled to between 40000 and 50000 cp. Aqueous gel34 a may comprise guar gum, xanthan gum, methylcellulose, or the like,or a combination thereof.

In a further preferred embodiment, suspension 34 further comprises agrit-like substance of a predetermined granularity mixed into aqueousgel 34 a in a predetermined ratio, e.g. 80 grit garnet mixed by volumein aqueous gel 34 a in a one part 80 grit garnet to one-and-a-half ratiopart gel 34 a ratio.

Body 40 may be manipulatable by a remotely operated vehicle (“ROV”). Ina currently preferred embodiment, body 40 further comprises first inlet42 fluidly coupled to source 20 of high pressure fluid 22 to accept highpressure fluid 22, e.g. first inlet 42 may be fluidly coupled to source20 via hose 24.

Body 40 may further comprise second inlet 44 fluidly and non-aspiratedlycoupled to source 30 of abrasive materials 32 in suspension 34, e.g. viahose 36.

Cutting nozzle 46 is disposed within or about body 40 and is in fluidcommunication with both first inlet 42 and second inlet 44.

In a currently envisioned alternative embodiment, referring now to FIG.2, system 10 comprises source 30 of abrasive materials 32 in suspension34; first pump 31 in fluid communication with source 30; second pump 21in fluid communication with first pump 31 and in further fluidcommunication with fluid 22; and body 40.

Second pump 21 is capable of creating a pressurized mix of abrasivematerials 32, which are preferably mixed or otherwise suspended insuspension 34, with fluid 22. Second pump 21 further comprises outlet 23for pressurized mixture 41.

Body 40 further comprises first inlet 42 fluidly coupled to outlet 23 toaccept pressurized mixture 41 and cutting nozzle 46 which is in fluidcommunication with pressurized mixture 41. As with the first describedembodiment, body 40 may be manipulatable by an ROV.

In the operation of an exemplary embodiment, referring now to FIG. 3,first fluid 22 is mixed with second fluid 38 that further comprisesabrasive materials 32 in a non-aspirated suspension 34 to create mixture41. Mixture 41, comprising a wet abrasive, is then pressurized anddelivered to cutting nozzle 46 underwater.

In an alternative method of use, mixture 41 (FIG. 1) is delivered tocutting nozzle 46 (FIG. 1) underwater by pressuring abrasive materials32 (FIG. 1) in non-aspirated suspension 34 (FIG. 1); pressurizing fluid22 (FIG. 1); and providing pressurized abrasive materials 32 innon-aspirated suspension and pressurized fluid 22 to cutting nozzle 46underwater.

An alternate method of delivering a wet abrasive to a cutting nozzleunderwater is illustrated by the flowchart of FIG. 4. One step involvesthe mixing a first fluid with a second fluid without a gas 50, whereinthe second fluid comprises an abrasive materials in a suspension. Nextthe mixture is pressured without a gas 51. Finally, the pressurizedmixture is delivered to a cutting nozzle underwater 52.

It will be understood that various changes in the details, materials,and arrangements of the parts which have been described and illustratedabove in order to explain the nature of this invention may be made bythose skilled in the art without departing from the principle and scopeof the invention as recited in the following claims.

1. A system for cutting a material underwater, comprising: a. a sourceof high pressure fluid; b. a source of abrasive materials in asuspension; and c. a body, further comprising: i. a first inlet fluidlycoupled to the source of high pressure fluid to accept the high pressurefluid; ii. a second inlet fluidly and non-aspiratedly coupled to thesource of abrasive materials in a suspension; and iii. a cutting head influid communication with both the first inlet and the second inlet.
 2. Asystem according to claim 1, wherein the fluid further comprises water.3. A system according to claim 1, wherein the source of high pressurefluid is a pump.
 4. A system according to claim 1, further comprising ahose in fluid communication between the source of high pressure fluidand the body.
 5. A system according to claim 1, wherein the suspensioncomprises an aqueous gel.
 6. A system according to claim 5, wherein thesuspension is gelled to between 30000 and 60000 cp.
 7. A systemaccording to claim 5, wherein the aqueous gel comprises at least one of(i) guar gum, (ii) xanthan gum, or (iii) methylcellulose.
 8. A systemaccording to claim 1 wherein the abrasive material comprises at leastone of (i) garnet, (ii) bauxite, (iii) sand, or (iv) taconite.
 9. Asystem according to claim 1, wherein the suspension comprises 80 gritgarnet mixed by volume in an aqueous gel in a one part 80 grit garnet tobetween a ration of around one part gel to around three parts gel.
 10. Asystem according to claim 1, further comprising a hose in fluidcommunication between the source of abrasive materials in a suspensionand the body.
 11. A system according to claim 1, wherein the system isconfigured for displacement subsea without a need for a surface sourceof either high pressure fluid or abrasive material.
 12. A systemaccording to claim 1, wherein the body is adapted to be manipulated by aremotely operated vehicle.
 13. A system for cutting a materialunderwater, comprising: a. a source of abrasive materials in asuspension; b. a first pump in fluid communication with the source ofabrasive materials in the suspension; c. a second pump in fluidcommunication with the first pump and in further fluid communicationwith a fluid, the second pump capable of creating a non-aspirated,pressurized mix of the abrasive materials in the suspension with thefluid, the second pump further comprising an outlet for the pressurizedmix; and d. a body, further comprising: i. a first inlet fluidly coupledto the outlet to accept the pressurized mix; and ii. a cutting head influid communication with the pressurized mix.
 14. A system according toclaim 13, wherein the body is adapted to be manipulated by a remotelyoperated vehicle.
 15. A method of delivering a wet abrasive to a cuttingnozzle underwater, comprising: a. mixing a first fluid with a secondfluid without a gas, the second fluid comprising abrasive materials in asuspension; b. pressuring the mixture without a gas; and c. deliveringthe pressurized mixture to a cutting nozzle underwater.
 16. A method ofdelivering a wet abrasive to a cutting nozzle underwater, comprising: a.pressuring abrasive materials in a suspension without use of a gas; b.pressurizing a fluid without use of a gas; and c. providing thepressurized abrasive materials in a non-aspirated suspension and thepressurized fluid to a cutting nozzle underwater.